There's a definite air of mystery surrounding the Americans' opponent in their World Cup opener today.

North Korea plays few games, just five in the past six months, giving opposing coaches little opportunity for scouting. None of the players play overseas professionally. Only two of the North Koreans have previous World Cup experience.

North Korea is also the youngest team in the tournament, with 14 players 20 or younger — including two 16-year-olds and two 17-year-olds — and just one who is 30. Only five players have 10 or more appearances with the senior national team.

"It's really difficult when you don't see much of a team and you're not familiar with how they play," defender Ali Krieger said Monday after the U.S. training session at Rudolf-Harbig Stadium. "We might get some nerves because you don't know what to expect."

Goalkeeper Hope Solo said it's even hard to see footage of their games. The Americans are basically keying off two recent North Korean games — against Germany and China — and figuring that's the lineup they'll face.

"They are technical, they're comfortable with the ball, they're reading the game very well and I think they're one of the best teams in the world between the boxes," U.S. coach Pia Sundhage said. "But the game and the field's a little bit bigger. You have to add the two boxes."

The Americans have played North Korea three times, all at the World Cup. The United States dominated the first two meetings, winning each game 3-0. But North Korea has made it a priority to improve, and the results are beginning to show.

At the 2007 World Cup, the Americans went down 2-1 before Heather O'Reilly scored to salvage a draw. The North Koreans won the under-20 title in 2006 and were runnersup to the Americans two years later.

With details about the North Koreans so scarce, there's little for the Americans to obsess over. Instead, the Americans have spent most of their preparation focusing on themselves. And there's plenty of material there.

The Americans are the top-ranked team in the world and the defending Olympic gold medalists. But it has been a rough couple of months for the two-time World Cup champs, with an upset by Mexico in regional qualifying and losses to Sweden and England since January.

A lot of people wrote the United States off after it dropped its opener at the Beijing Games, too. The Americans responded with five straight wins.

"The team we have is just a fantastic team," Sundhage said. "We have experienced players. The soccer we're playing right now is pretty good."